The invention relates to the manufacture of printheads for ink jet printers. More particularly, the invention relates to the removal of debris from nozzle plates during the manufacture of printheads.
Nozzle plates of the type used in ink jet printheads can be made by laser ablating a polyimide material to define ink flow features. During this process, debris, primarily loose polyimide material, may become present on the ablated material and remain after the flow features have been formed. This debris is undesirable, as it may clog the flow features, cause poor adhesion when the nozzle plate is subsequently attached to a heater chip, or be otherwise detrimental to the manufacturing process and function of the resulting printhead.
One common method for removing the debris is by adding a water-soluble sacrificial layer to the topside of the nozzle plate material. The debris lands on this layer and is removed by a high-pressure water spray. However, the desire for faster printers has led to the use of longer heater chips and hence, longer arrays of nozzles. Also, the desire for higher quality print has led to smaller flow features on nozzle plates that are very close together, e.g.,  less than 10 xcexcm. However, for various reasons, water spray techniques are generally unsuitable for cleaning debris from longer plates and/or plates having flow features that are very close together.
Accordingly, there is a need in the art for improvements in the manufacture of printheads and, in particular, in the making of nozzle plates by laser ablation.
With regard to the foregoing, the invention provides a method for forming a nozzle plate for an ink jet printer by laser ablation.
In a preferred embodiment, the method includes the steps of laser ablating a first portion of a nozzle plate material to partially form topographical flow features on the material. Next, a second portion of the nozzle plate material is ablated to form second topographical features. During this second ablation step, debris generated during ablation can travel to the first portion. Thus, additional ablation is performed to additionally form the first flow features and, in the process, remove debris generated during ablation of the second flow features.
An advantage of the invention is that it enables ablation of longer nozzle plates while avoiding the presence of debris on the finished nozzle plate. For example, debris from the first step of partially forming the first flow features which may land on the second portion is removed during formation of the second flow features. Debris from the formation of the second flow features is removed from the first portion when the first flow features are additionally formed. The debris from the additional formation of the first flow features is substantially negligible. If desired, the ablation may be performed in more than three steps, such that each step produces less and less debris.
In another aspect, the invention relates to a method for forming a nozzle plate for an ink jet printer by laser ablation.
In a preferred embodiment, the method includes the steps of:
(a) laser ablating a nozzle plate material to form topographical features on the nozzle plate material;
(b) providing a mask having an inner open area surrounded by a outer shielded area and positioning the mask on the nozzle plate material so that the topographical features are within the inner open area and surrounded by the outer shielded area; and
(c) additionally laser ablating the inner open area of the mask to clean debris from the nozzle plate material, wherein such additional laser ablation causes debris located between one or more of the topographical features to travel away from the topographical features and the inner open area.
This method is particularly suitable for use in removing debris from between flow features of the nozzle plate that are closely spaced relative to one another.